When Senate Judiciary Committee Chairman Chuck Grassley, a Republican from Iowa, announced a hearing for next Monday to air a decades-old sexual-assault allegation against Supreme Court nominee Brett Kavanaugh, it didn't end the debate over how the Senate should handle the charges.

It intensified it.

Democrats are calling for a full FBI investigation of the allegation before a hearing, saying Monday is too soon.

"I'd have the professionals go in there, seek corroborating evidence, talk to the people involved, certainly talk to the third person who they claimed was there, and that hasn't been done," Democratic Sen. Patrick Leahy of Vermont, a longtime member of the Judiciary Committee and a former chairman, told NPR's Morning Edition. "This might take a week or two to get all of this together, but what difference does one or two weeks make when you're talking about a lifetime appointment."

Republicans and the Trump White House argue that isn't the FBI's role. The Justice Department seems to agree. In a statement, a Justice Department spokeswoman said the FBI — which has added a letter from Christine Blasey Ford to Kavanaugh's already completed background report file — had already done all it was going to do, because "the allegation does not involve any potential federal crime."

"The FBI does not make any judgment about the credibility or significance of any allegation," the statement reads. "The purpose of a background investigation is to determine whether the nominee could pose a risk to the national security of the United States. The allegation does not involve any potential federal crime. The FBI's role in such matters is to provide information for the use of the decision makers."

Grassley was more definitive in an interview with conservative radio host Hugh Hewitt Tuesday morning.

"The FBI investigation of Judge Kavanaugh is closed," he said. "The FBI is not doing any further investigation."

Blasey Ford has accused Kavanaugh of a sexual attack when they were both in high school. She sent a letter to her congresswoman, Rep. Anna Eshoo, in July, which made its way to Sen. Dianne Feinstein, a Democrat from California and ranking member of the Judiciary Committee. Blasey Ford asked for confidentiality, and the allegation was not made public — until this past weekend.

That's when she came forward for the first time publicly in an interview with The Washington Post. She detailed her memories of the incident, saying that Kavanaugh pulled her into a bedroom along with another boy, then allegedly groped her, trying to remove her clothing, and put his hand over her mouth to muffle her screams.

Kavanaugh responded through the White House with a categorical denial.

"This is a completely false allegation," he said. "I have never done anything like what the accuser describes — to her or to anyone. Because this never happened, I had no idea who was making this accusation until she identified herself yesterday. I am willing to talk to the Senate Judiciary Committee in any way the Committee deems appropriate to refute this false allegation, from 36 years ago, and defend my integrity."

He will do that in a scheduled hearing Monday, in what Democrats worry will be a replay of another he-said, she-said exercise in 1991 when Anita Hill came forward with sexual harassment allegations against then-Supreme Court nominee Clarence Thomas.

Democrats complained that there was not a thorough FBI investigation of the allegations that took place, and no major witnesses other than Hill and Thomas who were called. Monday's planned hearing seems to be following a similar pattern.

Grassley told Hewitt Tuesday that, "Yes," there will only be two witnesses Monday. "We've got two people involved," Grassley said, "and two people ought to be able to present their stories and then we'll have to be the jury."

Grassley added, "Accusers deserve to be heard and, after they're heard and we also have a responsibility to hear Judge Kavanaugh, and I want to hear from Dr. Ford, and she deserves to be heard, because these are serious accusations."

Grassley said it isn't even 100 percent certain at this point whether Ford or Kavanaugh will testify first, though he is inclined to have Ford go first.

On Morning Edition Tuesday, Leahy suggested that another man who was allegedly in the room at the time of the encounter be called before the committee.

There were other potential witnesses who came forward before the Hill-Thomas hearings, and then-Chairman Joe Biden declined to let them testify, something he now has said publicly he regrets.

Democrats argue that other witnesses could provide context and verify or refute parts of the stories that either person tells. For example, a friend and neighbor of Blasey Ford's told the San Jose Mercury News that Blasey Ford told her of the incident in 2017 before Kavanaugh was nominated.

The paper reports:

"It's been difficult for Blasey Ford over the years, [Blasey Ford] told [Rebecca] White, because the judge's name would come up as 'a super powerful guy and he might be a contender for a Supreme Court position one day.' "

Grassley told Hewitt that he has not heard from Blasey Ford yet, saying the committee has reached out to her.

"We still haven't heard from Dr. Ford, so do they want to have the hearing or not?" Grassley said.

Blasey Ford's attorneys told NPR's Morning Edition and other outlets that Ford is willing to testify.

Grassley told Hewitt he hoped the hearing wouldn't devolve into a circuslike atmosphere. The days of Kavanaugh confirmation hearings were often interrupted by protesters, and Republicans accused Democrats — especially those possible 2020 presidential candidates — of grandstanding.

"I'd like to see 21 members of our committee listen patiently to both witnesses," Grassley said, "and kind of act like a jury and then wait until you hear all the evidence, and then make your mind up afterwards. And I'm going to be respectful, and I hope my colleagues will be too."

Grassley also couldn't answer whether each senator will get one or two rounds of questions. He said that hasn't been worked out and pointed to the Democrats, noting that there hasn't been a lot of cooperation from Democratic staff.

Hewitt asked whether there was any thought of having a female lawyer or someone like former Republican Sen. Kelly Ayotte of New Hampshire come in to do the questioning since there are no Republican women on the Judiciary Comittee.

"You're raising legitimate questions that are still on our mind," Grassley said, "and so these details are still being worked out."

All that's certain at the moment is that a hearing is scheduled for Monday, and that both Kavanaugh and Blasey Ford have been invited and have expressed an openness to participating to publicly tell their side of the story.

For Republicans, who wanted Kavanaugh confirmed in time for the start of the new Supreme Court session beginning Oct. 1, a week or two would throw that timeline off. More important, Republicans want him confirmed before November's elections in the off chance that Democrats take control of the Senate.

Then again, this new allegation has already cast a massive shadow over Kavanaugh's nomination. Kavanaugh's supporters in the Senate and the White House question Democrats' motives, suggesting all they really want is to delay a confirmation vote.

"He wasn't going to vote for Brett Kavanaugh to be on the Supreme Court in the first place," Kellyanne Conway, counselor to the president, said of Leahy, who appeared before her on the PBS NewsHour Monday night. "A lot of people in the Senate weren't going to vote for him anyway."

Still, Conway and other Republicans are going out of their way to say they want Ford and Kavanaugh to be heard.

"It's good to hear from both the accuser and the accused here," Conway said, "and allow the Senate to weigh what they learn in those exchanges, along with the mountain of other testimonial evidence and other statements of support and endorsements of Brett Kavanaugh by the women he's known all throughout his life."